key.c

该程序是基于c8051f020的平台

#define  Key
#include <Key.h>

// 主程序,通过调用"读键值" 和 "译码" 程序, 将键值返回给主调函数
uchar Key_Word(void)
{
   unsigned char key,m;
   unsigned char key_decode = 0xff  ;

   P1=0xf0;
   m=P1;
   if(m!=0xf0)            //有输入
     {
        key_delay(100,100);   //去抖
        P1=0xf0;
        m=P1;
        if(m!=0xf0)       //确认有键
          {
             key=Read();
             key_decode=Decode(key);

             P1=0xf0;
             while(P1!=0xf0);//等待键释放
           }
      }
    return(key_decode);
}

//读键值 ------------------

uchar Read(void)
{
 uchar key,H,L;
 P1=0xf0;
 key_delay(1,10);
 H=P1&0XF0;
//---------------
 key_delay(1,10);
 P1=0x0f;
 key_delay(1,10);
 L=P1&0X0F;
//---------------
 key=H|L;
 key=~key;
 return(key);
}
//译码

uchar Decode(uchar x)
{
  uchar i,j,k;
  for(i=0;i<4;i++)
    for(j=0;j<4;j++)      
       {
         if(x==key_s[i][j])
         k=key_t[i][j];
       }
  return(k);
 }
//////////////////////////////////////////

void key_delay(uchar t1,t2)
{ 
  uchar i,j;
  for(i=0;i<t1;i++)
    for(j=0;j<t2;j++);
}